SPECIFICATIONS
Input Level:
-10 to +40 dB unbalanced
Output Level:
-10 to +2 dB balanced XLR Male (pin 2 +)
Bandwidth:
1 Hz to 50 kHz
S/N Ratio:
100 dB
Jacks:
(2) 1/4" phone, (1) XLR male
Conrols:
Attenuator switch, Ground Lift switch,
Power:
9 - 48 VDC Phantom Powered
Size:
2" x 3.5" x 5"
J1
PC 1/4
1
2
4
3
SW1A
ALPHASW
ATTENUATOR
8
7
5
6
SW1B
ALPHASW
R5
10K
1
2
3
J3
XLR M PC
R4
1M
Q1
PN4857
Q2
PN4857
R3
1M
R7
100K
R8
10K
R9
1M
J2
PC 1/4
R2
3.3K
R1
3.3K
R6
10K
GROUND LIFT
3
1
2
SW2
SPST
Date:
July 18, 1994
Sheet
of
Size
Document Number
REV
A
ADB2.SCH
B
Title
ADB2 PHANTOM DIRECT BOX
ROLLS CORPORATION
Congratulations and thank you for your purchase of the ADB2 Phantom.
The ADB2 is designed to provide lasting value and usefulness. It is
intended for sending unbalanced signals (up to +40 dB) to a mixing
console or other professional input device. The unit has no transformer,
so stray field pickup is nonexistent. The ADB2 is powered by standard
microphone phantom power from 9 - 48 VDC and uses discrete low-noise
differential drivers to make it very quiet. The unit has two 1/4" input jacks
wired in parallel, a male XLR output jack, a ground lift switch, and a three-
position attenuator switch.
DESCRIPTION
INPUTS: Two 1/4" unbalanced jacks - wired together in parallel. For
connection to line or instrument level signals.
OUTPUT: One male XLR jack for connection to mixing console or other
input device carrying phantom power.
ATTENUATOR SWITCH: Decreases the input signal by the indicated
amount. At 0 dB the signal is not attenuated, at the 20 and 40 dB settings,
the signal is dropped by that amount.
GROUND LIFT: Removes the ground connection of the 1/4" and XLR
jacks from the chassis ground.
INSTALLATION
In order for the ADB2 to function it must be connected to a microphone
phantom power source with a balanced XLR cord. The input may be
anything from a speaker source such as a music amplifier, VCR or
projector, to an instrument such as a guitar or High-impedance micro-
phone. Care should be taken to overdrive the ADB2 or there will be a
distorted sound from the unit. Use the lowest attenuator setting that gives
distortion free sound. The ground lift switch should be in the position that
yields the lowest noise.
INPUT
ATTENUATOR
0 dB
-20 dB
-40 dB
GROUND LIFT
GND
LIFT
OUTPUT
PHANTOM
DIRECT BOX
ADB2